1. Field of the Invention
The present invention relates to a photomultiplier tube for detecting incident light from outside,
2. Related Background Art
Conventionally, compact photomultiplier tubes by using of fine processing technology have been developed. For example, a flat surface-type photomultiplier tube which is arranged with a photocathode, dynodes and an anode on a translucent insulating substrate is known (refer to Patent Document 1 given below). The above-described structure makes it possible to detect weak light at a high degree of reliability and also to downsize a device.    Patent Document 1: U.S. Pat. No. 5,264,693